Apparatus for shaping the millstones for rectifying gear teeth



66L 4, 3 VQIGNIE'R 1,880,612

APPARATUS FOR SHAPING THE MILLSTONES FOR REGTIFYING GEAR TEETH Filed June 28, 1929 4Sheets-Sheet l //v vEw-ra z J 6 5 TA V5 15 VO/G/V/ER Q-fi'iih 4, 3932. E VQIGNIER 3,880,612

APPARATUS FOR SHAPING THE MILLSTONES FOR REGTIF'YING GEAR TEETH Filed June 28. 92 4 Sheets-Sheet 2 Oct. 4, 19321. yo 1,880,612

APPARATUS FOR SHAPING THE MILLSTONES FOR RECTIFYING GEAR TEETH Filed June 28, 1929 4 Sheets-Sheet 3 61 IND/ZNTOQ Gus TA vs E. i O/G we A T TOE/V5 Y5 @ct. 4 1932. G. E. VOIGNEER 3983,5612

APPARATUS FOR SHAPING THE MILLSTONES FOR RECTIFYING GEAR TEETH 4 Sheets-Sheet 4 Filed June 28. 1929 101 108 //v VEN roe 6 s TA vs 5. I/OIG/Y/E'Q Patented Octi4,1932 I l,880,612

UNITEDQSTATES PATENT omen GUSTAVE ERNEST VOICiNIEF, OF PARIS,- FRANCE APPARATUS non snnrme THE iurus'ronns For. nno'rrrvme Gm 'rnn'rn A Application filed J'une 28, 1929, Serial No. 374,503; and in France I 1y 27, 1 928.

The present invention-has for its object to Fig. 7 is a partial view in elevation of the provide an apparatus for shaping the millsame apparatus as above. stones adapted for rectifying gear teeth. The apparatus illustrated diagrammatical- This apparatus is characterized by the fact ly in Fig. 1 is intended to be employed for x that the outline of the tooth (generated by the production of an outline approaching a the point of a diamond which constitutes the development of a circle of a millstone l adapttool) results in sliding movements of two rods ed to rectify the teeth of a toothed wheel sliding in guides, one of these guides having with the center. 0, the pitch circle being inf a rotarv movement about a fixed point and dicated at2 whilst the circles passing through 19' the other a translatory movement. the bottom and tops of the teeth are respec- The invention also has for its object: tively'indicated at 3 and 4. A device for mounting the apparatus prop- The apparatus is provided with a frameer for efiectin g successively, and without dis- Work 5 which may, for example, be mounted mounting, the rectification of the gears and upon a pivot bolt (Fig. 2) which passes rectification; I This framework isrepresentedby a single.

A method of construction of this apparatus block in the drawings, but in reality itmay provided with an adjustable and automaticalbe composed of a number. of parts enabling ly-operating device characterized in that the it to.be employed for toothed wheels of dif- I :3 suitable displacement of the point ofthe tool ferent diameters. r is obtained'by the convergence ofthe mov- The framework 5 is provided with two able members towards an imaginary axis of straight line or circular guides secured therew-hich the position varies according to the to in adjustable positions, as regards their, number of teeth of the gear to be rectified and direction, by graduated frames and, as realso according to the tooth profile and angle gardsc eir straight line movement at right or line of pressure. angles, by divided guides, this frame and.

The various movements to be imparted to these guides being capable of being providthe apparatus mounted and constructed in ed, if necessary, with verniers and micromthis manner are imparted durirrg the course eter screws.

Figil shows diagrammatically and by way drawn .ir'om the tangentlal point making of example different possible adjustments with the radius drawn from the center 0 to (the adjusting devices not beingshown) of the beginning of the outline, an angle 8' an apparatus constructed in accordance with which is double the angle or of pressure, as the invention. indicated in Fig.1.

Fig. 2 also shows diagrammatically the The other guide 8 has a general direction manner in which the apparatus is mounted. which is approximately that of a radius of in accordance with the invention. the bottom circle. 9

Fig. 3 is an elevation in detail, partly in These two guides therefore have directions section and partly broken away, of an appas substantially at right angles (in the accomratus constructed in accordance with the inanying drawings they have been shown as F Vention. being rectilinear and disposed respectively Fig. 4 is a planof the same apparatus. along a tangent of the ottom circle and Fig. 5 is an end view'of the same appaalong the radius to the tangential point, but

ratus. these particular positions are shown mere- "Fig. 6 shows a plan of, an apparatus con- 1y byway of example).

5o structed according to the invention and driv- In the guide 7 may move longitudinally 00 en by a motor. a slide 9, the movement of the said slide be- ]3 the shaping of the millstones adapted for this through an opening 6 in the framework. 65 1 30 of the operation eit er by the operator him- \The guides include theguide 7 whose gen self or by any suitable driving system. eral direction approaches that of a tangent In the accompanying drawings to the bottom circle 3 of the wheel, the radius y of the frameworlg angles to the axis of the end 16 the diamond point millstone the other end 17 of the slide being provided with a pivot on which is mounted I guides 7 and 8 cular guides are applied to the apparatus, to select for them any optima curvatures) 55 the slide 9, any

'(Fi e2): 'A f ramework 22 supports the yari 'ing determined, for example, by a screw '10 engaging with a screw threaded portion 11 and oprableby means of a wheel-12. It w1ll however be under- 5 stood that any other methodofmoving the slide may be adopte To the slide}? is pivoted a guide 13 formihg a movable guide attached to a rod 14: secured in a position whichis almostat right guide' 13. 1 a In the movable guide 13 ay movelongi- .tudinally the slide 15 which carries at its for shaping the a rod 18 pivoting about afixed point 19 whose position is adjustable on the frame.

work. 1

The free end of the rod 14 may move lon- 20' g'itudinally in a movableguide 20 pivoted can move in the guide 8 on a slide 21 which after preliminary marking.

Under these conditions the end of the diamond describes a curve having an angular point (or a point of retrogressionaccording to the adjustment) which may be brought, by adjustment, on or within the bottom or base circle.

For a: wheel of given diameter andtooth profile it is thus possible to obtain a more or less elongated outline of the mathematical outlines, but such that practical and correct development of the toothed wheels gearing with one another, aving regard to the conditions of speed, rotation, the couple transmitted and the elas: ticity of the material of 'which the gears are made and in general of all the factors'which intervene for altering, during movement, the 40 shape of theteeth when at rest.

J The adjustments provided on an apparatus constructedas hereinb'efore described are:

a. The orientation and the position of the (it-is also possible, when cir b. The angle included betwenthe 50614 I l and them vable guide 13.

0. The ength of the tool-carrying ruler d. The length of the rod 18. Y a

e. I-he positionof the fixed point 19.

It is useless to provide an adjustment of the position of the axis of the guide 13 on more than an adjustment for theposi tion' of the axis of the guide 20 onthe slide 21, these positions corresponding simply inthe first'case toan unwedging to an unwedging, without modification of the orientation of the guide 8. f

' The mountingof the apparatus above deed .is efiected' in the following manner /the nut 30, but

it permits of 5;

. by the engagement of the nuts of theaxes in height of the guide 7 and in the second case members forming 23 in which is adapted to move and be secured, in any selected position, a slide 24 in the form of a column bored vertically to receive the shaft 25 on which. is secured'the pinion 26 to be rectified. d The shaft 25 is free to turn in the slide 245 and is held therein in any an lar position corresponding Withthe gra nations of a dividing device said shaft.

The upper face of the said framework 22 is in the form of a bench and receives I 1. A large carriage 27 on which is mounted. the m illstone 1. a 2.- A small carriage 28 on which is pivoted at 0 the shaping apparatus. 1

The two carriage 27 and 28 are secured respectively by nuts 29 and 30 through which mounted at the lower end of ,passes a screw spindle of which the portion 31,w-hich engages with the nut 29 is of the same pitch as the portion 32 passing through the portion 32 has a double thread in such a manner that upon turning the crank 33, secured to the spindle, other, the carriages'27 and 28 move longitudinally andin the same direction but at linear speeds which are respectively'in the pro- & portion of one for the carriage 27 to two for the carriage 28. siniilar result would be obtained by'making, the portion 32 of the spindle of a pitch twice thatofthe portion 31.

he millstone 1 is-mounted on a shaft 34; which may be rotated by any suitable driving neans'anlvvhich rests in a bearing secured in a' plate 35 of which the base can move transversely 'on thecarriage 27 and be looked on the said carriage in any selected position.

yWhen mounti ng the carriages on the bench 29 and 30 with the screw spindle 3132, this mounting is effected in such a manner that the distance a of the pinion 26 and of the wheel 1 are equal of rotation of the mill'stone 1 and the pivotal axis t) of the shaping apparatus, this condi- -tion being necessary n order that the radius the axis 'ofthe sta- The millstone i being rotated, the pinion to be rectified is presented in front of it by vertical movement in such a manner that the millstone engages in the spice between two the entire machine and one of its lateral sides carries a vertical guide with a single thread, whilst in one direction or the to the distance Z) between the axis the spindle "of the circle and been" rectified.

When by reason of wear the millstone no longer has'the correct shape for the rectification, the pinion 26 is removed and the crank 33 is operated in such a manner that the millstone 1 is fed towards the shaft through a distance equal to 'its radial wear. At the same time the carriage 28 hasfollowedth-is movement and the diamond point 16 of the shaping apparatus is placedon the circle of origin of the millstone corresponding] with the base circle of the pinion to be rectified.

The shaping app fr'atus .being operated by the wheel 12 and the millstone 1 being always in rotation, theoutline of the said millstone is correctl re-establishedby developing acircle suitab e for the dimensions of the pinion to be rectified and to the selected profile when the selection of the dimensions of the rod 18 and of the position of the stationary point 19 have been properly made.

Figs. 3, 4, 5, 6 and 7 show the detailed construction of the apparatus proper; As will .be seen in the drawings this apparatus is provided with a first carriage referred to as the driving carriage which maybe actuated by ii the wheel 36 operated by hand or by a double clutch system when the device is operated by a motor (which-isthe case in Figs. 6 and 7).

The driving carriage is composed of a framework 37 which may be secured to a securing foot38 by meansof a bolt 39. The securing of the framework of the carriage may however be accomplished in different ways and the mode illustrated is given only by way of example.

To the framework 37 are secured two bearings 40 and 41 which support and hold a screw 42 to which is secured the wheel 36.

The screw'42 receives a nut 43 which can move alon I the framework in which it-is guided by t eguide 44 (Fig.5).

The U-shaped member 45 (Fig. 5) completes the driving carriage and can move on.

the guide 44. Awedge 45 enables any play which may exist between the members 37 and 45 to be eliminated;

The member 45 which can move longitudinally on the member 37 is longer than the latter so as to permit of a sufiiciently large relative longitudinal movement. On the up per face of the member 45 is'provlded a longitudinal mortise 46 in which canmov an arm 47 securedto the'nut 43. The upper end of the arm47 carries a finger 48 at right angles to the axis of the carriage.

At the endsof the member 45 are secured this space having arates the base circle and. the

plates 49 and 50, the first (49) being referred to as the stop plate and the second (50) as the holding-plate of the spring guide. These two pllaltes at the same time serve to protect the s 1 e.

A spring 51 located between the plate 50 and the bearing 41 constantly tends to press the carriage against the stop plate 49.

In the mortise 46 of themember 45 can 52 (Fig. 4 which may secured.

move a sto in any so ected position bymeans of a nut 53.

On the finger48, which is in the form of a shaft, is freely mounted a fork 54 (Fig. 4, but shown more clearly in. Fig.6) which ma have any selected shape and is provi 'ed with a notch 55 which 'may have any dimensions and any suitable inclination. The fork 54 is held in position against the set square 56 by a guide 57 cured to the set square.

When the screw 42 is fork moves relatively to the two longitudinal and transverse axes of the setsqpare 56.

It therefore causes the position of a roller bearing 58 (Figs. 3 and 6) to'be changed,

and this more or less the inclination of the prongs of the fork,

relatively to the general axis 'of the appa- I Q ratus.

If the turning of the screw is continued until the arm 47 meets the stop 52 then, when contact is made between these two parts, the fork 54 can no-longer move relatively to the set square 56. Themeinber 45 is then, an 1 dr the constant action of the spring 51., V

moved rearwardlythrough a distance equal radially se 3 bottom of t e to or greater than that which teeth of the pinion to be rectified. By turning the screw 42 to the left the various members of thesystem are returned to their initial positions. Y r

The set square 56 is secured to the driving carriage by means of two screws 58 and 5,9

in such a position that its longitudinal axis forms with the axis of the carriage an angle equal to the pressure-angle. H s fon the set square is mounted a member 60 ig. 5) refe'nred teas the die support,

secured-to the set sguare by-the screws 61 and 62 (Fig. 4) and at an lnclination relatively to the set square. corresponding with the pressure angle. The memberf60 can move longitudinally on the set square in the mor tise 63 (Fig. 3).

The member 60 carries a die '64 held without lay by wedgesj65 and 66 (Fig. '4) secured by screws 67 and by-a thickness wedge 63 which may be adjusted from the side by means of suitable screws and lock (nuts.

The die 64 i provided with a hole which receives a ring'69 having a shoulder and which serves to seat a vertical shaft 70 of (Figs. '4 and 5) 'se-j.

turned by means of i the wheel 36, to the right for example, the

rapidly according to which theupper portion 71 is formed as a guide. I

. The lateral play which may exist in this guide is taken up by a bolt 72 and-a lock 6 nut 73.

i The shaft 70 carries at the lower portion the ball bearing 58 referred to as the,driving roller of the apparatus and which is At the lower end of the shaft 70 is mounted a square guide 74 which is enclosed in a square, but it ma be secured in any other manner, and whic ,is held by a nut 75. This square guide is placed at. right angles to the guide 71. Its outer end is held in a small transverse slide or guide 76 which at. the start imparts to it a position parallel to the driving carriage.

The u'id'e 76 itself engages with another guide 7 whose axis forms with the general axis of the driving carriage an angle equal to twice the pressure angle. The guide 77 is mounted in a support 78 of which the in- 5 clination is adjustable. Wedges are provided in the guides 76 and 77 so as to enable play to be taken up.

In the member 71 is fitted a. slide 7 9 which' is held therein without play by two izpper 'ort relatively to the horizontal axis passmg through the center of the millstone may be secure the rod 83. ismounted a T-shaped member through whose horizontal portion passes the rod 85 which carries the diamond point 86. A screw 87 secures the rod .85 in position in the support.

The rod 82 hinged at 81 to the' member 79 is secured,at its other end, to an eye 88 which enablesit to be pivotally secured to a second I .rod'element 89 by means of a bolt 90, this lat ter pivot enabling themember79 to be adjusted in position without it being necessary to change any member. 4 c

The small rod 89 isconnected to a rod-91 secured to a member 92 whos angular position relatively to the set square is variable which engages in a curved slot 94. This device enables a variable angle to beiimparted to the rod 91 according to the corrections to be made. in the'outline of the teeth.

ifThe" small rod 82 is to the-end-of placed between the two prongs of the fork] byalock nut 84 which enables the height of the'supportto be adjusted. Upon and may be adjusted by means of ascrew 93 The hinges v81 and 90 are suitably prothemember 7 by. anut 95 and a wedge 96 I adjusts theposition of the member .60 in the mortise 63. a a

The whole of the device-is secured to a feed carriage by means of the securing foot d8 of the member 37. The whole device can turn upon itself in order to permit of the advance or withdrawal of the millstone at the will of the operator. e

.The operation of the mechanism shown in Figs. 3, 4' and 5 'is as follows:' It will be understood that the mechanism illustrated in these figures is mounted asindi'cated in Fig-- ure 2, so that the diamond point 86, which is indicated at 16 in Fig. 2,-is positioned at the periphery of the millstone or grinding wheel, the latter being positioned on an adjustable carriage between the outlining or shaping apparatus and the support for the gear to be rectified. Themillstone is constantly rotated in any suitable manner, and whenthe same has become worn after grinding the teeth of a gear, the carriage supporting the shaping apparatus is moved toward the millstone until the diamond tool is opposite a point on a circle borresponding to the/ base circle of the gear teeth. The tool point is then given a movement along a predetermined curve to cut the millstone to the proper outline by suitably adjusting the fixed pivot 81 and then operatin the wheel 36, whereupon the diamond pointis given a movement having components parallel-to and'transversely to the axis of corresponds to the'pivot'; 19 of Fig. l the ourthe millstone. Itwill beunderstood that by adjustment ofithe pivot 81, which its vature of the path of the diamond point can be predetermined. The hereinabove described assembly functions in the following way (the elements in.

Figure 1 corresponding to those to be mentionedare indicated in parentheses): Element 60 is first locked in position on square tain the correctin 7 .56 as may bedesired; rod 91 (center 19) is then looked in position 'on support 92 to obeffect; slide 77 is also locked on position slide'21) as desired; final-' ly the angle between compass arms 82 and 89 is regulated by locking axis (length of link 18) with the foregoing structures in the positions indicated, operation of the machine will cause element 64 (slide 9) to move into element 60 (slide 7 thus displacing axis 70 and the u per part of slide 71 (slide 13);

rotation o the latter in element 64. is,con-'- trolled by a square 74 (rod 14.) which slides in guide 76 (movable slide; 20) the latter rotating in guldeway 77 (guideway 21) 3 Slide 71 assures proper orientation of rule- 7 9 (rule 15) which moves in the latter through a distance limited by compass 82, 90, 89 (element-18)- I v From the foregoing it maybe seen that the .point of articulation of slide 9,-of. guide-13- f moves along a-straight. tangent to the base of the teeth of a I will be seen that sli of slide 9 and guide 13,

speetively, and connecti requisite 'dia circle and that ide 13, or, more exactly, slide 15 does not escribe tangents to the real base circle, but to .a,curve which approaches the form of a circle, the radius of which differs from that of the base circle, the tangents obtained being correctedyby connecting rod 18 coupled at 17 to slide 15 and turning about a' fixe'd point 19 which may be adjusted.

,On account of this correcti g by the connecting rod, it becomes possi e, by moving fixed'point 19, to make any desired correction in the gear system. The pro e and diameter pinion thus corrected, though not of absolutely mathematical precision (this profile differs from the geometrical profile byless than a thousandth of a millimeter), are sufiiciently so to obtain silent operation. y"comparison of .F ,ig'ures 3, t and 5, it de 9 hf Figure 1 corre sponds to element 64, support ,60 to guide 7, axis 70 to the intersection of the axes slide 79 to slide 15, guide 76 and 77 to guide'20 and slide 21 reng rod 82 to connecting rod 18. Since support 00 is fixed to square 66 by screw 61 and 62, it sufiices to dis place said square to place shaft 70 on the meter of'the first circle. Element 7 maybe then'keyed in position relatively to element 60 at the required angle and there remains only'the steps of locking one, or the other of the two slides in position and placing the diamond atthe desired length to describe a tangent to the base circle, to procc ad with a milling operation.

The adjusting gear ofthe apparatus does not require very great precision. By means of connecting rod 18,- (or 82) any'desired correction may be effected by displacing fixed point 19. The movements of. the various members may be rendered automatic by means of a control by any suitable transmission means producing the rotation of the screw 42 with-- out itbe ng necessary to act on the wheel.

In th case the is apparatus is providedwith a device of the type illustrated in-' Figs. 6

in Figs. 3, 4

', meets the stop 5 and 7. This device differs from that shown and 5 in the provision of a dog clutch 97' keyed tothe shaft of the screw 42 for driving the latter. On this same shaft are also adapted toslide longitudinally two loose pulleys 98 and 99 each secured to a clutch member which may come into engagements withone of the faces of the-member 97. The two pulleys 98 and 99'are driven by belts, one of these belts, that which drives 'the pulley 99, for example, being crossed in such a mannor that the pulleys are caused to rotate in opposite directions. When the pulley 98 has ngagement with'the double clutch 97, the screw, forexample, turns in a clockwise direction and causes the finger 48-0f the nut- 43 to advance until the arm 47 a 2. At'this moment, and as time ser carriage has completed itsreturn' the member 45' moves back- 7 es the two loose pulleys 98 described above, wardly and driv and 99. r-

-During the return movement the pulley 98 pushesthe dog clutch 97-, which'can move longitudinally on its key and which is thus released from the two loose pulleys 98 and 99 these pulleys then continuing'to rotate on the shaft of the. screw.

The double dog clutch 97 is h by a fork 100 (Fig. 7 secure by means o f a nut 102.

The shaft 101 can slide in a framework 103 which may be secured to the end of the lower part 37 of the driving carriage by means of screws 104.- The said frameworkat the same ves as a bearing for the extension bf W 42 on which are mounted the clutch d to a shaft 101 the scre teeth. v I

The shaft 101 may be secured in the three positions which it may occupy (clutch teeth in engagement with the pulley 98, neutral, and in engagement with the pulley 99) by means of bolt 105 mounted in the framework 103 and which may engage with three sockets suitably'spaced and providedon the shaft. The bolt proper is located in a body 106 screwed by means of a screw thread into'the framework and enclosing .a spring 107 disposed between the belt 105 and a" screw 108,. and which tends constantly 'to ush the bolt into the notches. a

- Whenin View of the return movementof themember 45, the bolt 105 has escaped from the notch of the shaft 101 whichis towards the outside against the action of thetspring 107, it comes suddenly into the middle notch which produces a sudden longitudinal movement of the shaft 101 and, by means of the fork 100, and the disengagementof the teeth thecluteh 97 fromthe pulley 98 and its engagement with the pulley 99.

By reason of the opposite direction ofrotation ofthe two pulleys the screw 42 isthen driven Ban aiiti-clo carriage 45 moves t driving in its movement the teeth of the double clutch 97 until middle socket.-

The screw 42 continues to rotate in an anti clockwise direction until the whole of the device has again assumed the position which it occupies at the start. I To the fork 54is secured a rod 109 mounted in a shaft 110. he end of the fod 109'is free and formed as a fork, the prongs of this fork engaging in opposite sides of the shaft 101 which carries-at' its end a washer 111 of which the position can be adjusted by means of a nut 112. A certainamount of free space is left between the washer lll and theprongs/ of the fork at theend of the rod'109, which is h a manner that'when the 'adjustablejn suc movement and consequentlywhen the diamond has left the millstone, the fork,

eldandguided ckwise direction and the owards the stop plate 49 the bolt 105 falls into the j t,

pressing against the The two pulleys 98 and 99 are provided with grooves with w ich are engaged respectively the forks 113 and 114 adjustably fixed to a shaft 115 secured to a member 116 attached by screws 117 to the end of the member 45.

This device enables the. position of the loosepulleys to be adjusted on the shaft of the posed opposite only pro]ection meth screw 42.

An apparatus constructed in the manner above described permits of operating millstones capable of rectifying gears provided with any number of teeth and irrespective of the profile of these gears, the adjusting means above described enabling the apparatus to be adapted for .the production of various outlines.

When the tool is to pass from one faceof the millstone to the other it suffices to cause the set square to pivot in such a manner that it is caused to occupy relatively to the longitudinal axis of the apparatus, a position symmetrical to its positionot operation and so cause the diecarrying' member to turn about itself in its bearing and through asuitable angle.

If it is desired to outline the millstone on both sides at once an identical but duplicated apparatus may be constructed provided either with a single control finger 48 disthe millstone or' with two fingers placed symmetrically oneach side of the said millstone. v

I The apparatus may be enclosed by a sheet metal plate 118 which covers the mechanism whilst providing stone, the supportof the diamond being the above this casing.

It will be understood that the mechanism 7 which is. illustrated in Fig. 1 as also the I of mounting to which Fig. 2 applies are purely diagrammatic and for the vpassage of-the mill' to said holder may be controlled and a rod pivotally connected to said tool holder at a point spaced from the tool-carrying end thereof, the otherend ofsaid rodbein fixed, whereby upon linear movement of said guide it is simultaneously rotated.

2. Apparatus for on lining millstones for the rectification of gear teeth, comprising in combination, a stationary base, a-tool holder, a guide on said base slidably supporting said tool holder,"said guide being rotatable, and means for moving said guide linearly, where-' by the curve described by the end of a tool fixed to said holder may be controlled, said means including a second guide upon which said first guide is rotatably mounted.

3. Apparatus for outlining millstones for the rectification of gear teeth, comprising in combination, a' stationary base, a tool holder, aguide on said base slidably supporting said formoving said guide linearly, whereby the curve described by the end of a tool fixed to said holder may be controlled, a carriage I for supporting the millstone in a vertical plane, means for adjusting said millstone transversely of its face, a screw engaging said carriage for adjusting the same longitudinally, a second carriage for supporting the outlining apparatus, and a screwengaging said second carriage to move the latter longitudinally, said screws being connected to operate in unis on and being so formed that said second carriage moves twiceras rapidly as the first.

In testimony whereof I have signed this specification. v

GUSTAVE ERNEST VOIGNIEB.

that the adjusting devices arenot illustrated. It will also be understood that in the method of construction illustrated in Figs. 3, 4, 5, 6 and 7 the dimensions and the shapes ofthe various parts of the apparatus, as also the-pivots, guides and slides maybe constructed in any other preferred shape, and that the driving element may be of anytype without depart ing from the scope of the invention.

Iclaim: p I 1. Apparatus for outliningmillstori es for the rectification of gear teeth,' comprising in a'tool holder, base slidably supporting 'said rotatable,. means whereby the L a tool fixed A combination, a stationary-base, a guide on said tool holder, said guide 'bein for moving said guide linearly, curve described by the end of 

